An apparatus for delivering a measured amount of a low-boiling liquefied gas is known in which the liquefied gas can flow from an outlet of a thermally insulated cryogenic container.
Low-boiling liquefied gas is stored customarily in a thermally insulated cryogenic container and can be drawn off through an outlet. Particularly small quantities of low-boiling liquid gas may be measured out only with considerable difficulty because the gas arising at the outlet interrupts the continuous liquefied gas flow. Hence expensive devices were developed to attain a continuous liquefied gas flow for a measured small quantity of liquefied gas.
Thus a device according to German Pat. No. 34 02 292 for delivering a measured small amount of low-boiling liquefied gas is known in which the liquefied gas is located in one container which is surrounded by a second container so that an intermediate space arises between the containers. The liquefied gas can be drawn from the container through an outlet. Cold gas issues from the inner to the outer container and cools the entire apparatus so that the liquefied gas found in the inner container receives a minimum of heat from the exterior. The cold gas leaves the container by a gas outlet in the vicinity of the fluid outlet for the liquefied gas so that it surrounds the liquefied gas flowing out of the container. To confine the liquefied gas flowing out, a gas cushion is formed under an elevated pressure corresponding at least to the total gas pressure existing in the surroundings in the vicinity of the outlet.
A device for delivery of an uninterrupted stream of a cryogenic liquefied gas is known and described in German Open Patent Application No. 34 19 855. This device is connected with a delivery pipe and a degassing device downstream by a pressure regulator containing the cryogenic liquefied gas. Free liquefied gas leaves the degassing device while cold gas is conducted to a different location. Consequently an unbroken stream of cryogenic liquefied gas can be generated.
All known devices for delivering a measured amount of a liquefied gas, particularly for a small quantity, which deliver a continuous fluid flow are comparatively expensive.